1. Field of the Invention
The present invention relates to a timer movement, especially to a timer movement with a display for world time zones.
2. Description of Related Art
It is know that the internal exchange is getting more frequent and the transnational contact is getting popular due to the advance of the traffic and communication. In order to consider the factor with regard to the transmission of information and to the time difference, a clock possible to show the time of other time zones, or the so-called world time clock is developed for satisfying the needs.
Mostly, a conventional world time clock at the dial thereof is printed with a world map and a local time is looked up in the world map. The shortage involved in the conventional world time clock is that the dial appears too much complicated and it does not fulfill the criterion of human engineering from the standpoint of vision cognition and transmission.
For meeting the needs of displaying world time zones required by business men, the inventor of the present invention has developed a series of timer movement with a display for world time zones, for example the Taiwan Patent No. 480375 (equivalent to the China Patent No. 01120668.3, the U.S. Pat. No. 6,636,457, the European Patent No. EP 1291738 B1), the Taiwan Patent No. 1305873 (equivalent to the China Patent No. 200610075120.3, the U.S. Pat. No. 7,639,568), and the Taiwan Patent No. 1322933 (equivalent to the China Patent No. 200710079235.4, the U.S. Pat. No. 7,826,311). Each disclosed timer movement can be respectively applied in a clock, alarm or watch, and with the special design of adjusting the time zone with an intuitive manner, the developed products are very popular in domestic and international markets.
Each mentioned timer movement comprises a power source, a second counter, a minute counter, an hour counter and a time zone display. By turning a time zone adjustable ring installed on the time zone display, a first landmark of the local time zone is aligned with a fixed point for calibrating the local time, then turning the time zone adjustable ring to a second landmark of another time zone to the fixed point; at this moment, an inner gear ring of the time zone display drives a planetary idle gear and a planetary base gear to rotate, such that engaging hooks are in sequence buckled and positioned along each unidirectional ratchet hole, and a front hour wheel performs planetary motion about a minute wheel set on the planetary base gear for enabling an hour wheel meshed therewith to rotate, so as to displace an hour hand to the time in accordance with the time zone corresponding to the second landmark.
In addition, in each mentioned timer movement, at least two engaging hooks preset at the bottom of a substrate are respectively and sequentially buckled and positioned with plural unidirectional ratchet holes annularly arranged inside the time zone adjustable ring, or at least two engaging hooks preset at the bottom of a substrate are respectively and sequentially buckled and positioned with plural unidirectional ratchet holes annularly arranged at the top of the time zone adjustable ring; with the arrangement, the time zone adjustable ring is only provided with a unidirectional rotating and positioning function, so for the operation and selection of time zones, there is still some room for improvement.